JP2020182904A - Emulsifier including carboxymethylated cellulose - Google Patents

Abstract

To provide an emulsifier including carboxymethylated cellulose.SOLUTION: An emulsifier includes carboxymethylated cellulose in which the degree of carboxymethyl substitution is 0.20 or more, in which the degree of crystallinity of a cellulose I type is 50% or more, and in which a median diameter is in the range of 10.0-150.0 μm. The emulsifier can also additionally include an aqueous medium.SELECTED DRAWING: None

Description

The present invention relates to emulsifiers containing carboxymethyl cellulose. More specifically, it relates to an emulsifier containing carboxymethyl cellulose having a specific degree of carboxymethyl substitution, crystallinity of cellulose type I, and median diameter.

Carboxymethyl cellulose is a derivative of cellulose, and is obtained by ether-bonding a carboxymethyl group to a part of hydroxyl groups in glucose residues constituting the skeleton of cellulose. Carboxymethyl cellulose is non-toxic, and because of its thickening and thixotropic properties (hereinafter, also referred to as "thixotropic"), it is thickened in various fields such as food and drink, cosmetics, pharmaceuticals, industry, and construction. It is used as an agent and dispersion stabilizer.

Patent Document 1 describes carboxymethyl cellulose (hereinafter, also referred to as "CMC") as, for example, an emulsifier or protective colloid of an emulsion, a paint, an adhesive, a poultice, a coating agent, a builder of a synthetic detergent, or a soft cream. It is described to be used as a stabilizer such as jam or jam, an emulsion, a cream, a stabilizer for ointment, a swelling preparation, and a binder during tablet production.

Japanese Unexamined Patent Publication No. 2000-3430

Carboxymethyl cellulose is used as an additive in various fields such as foods and drinks, cosmetics, and water-based paints because of its properties such as viscosity thickening, water absorption, and water retention. These commonly used carboxymethyl celluloses are generally water-soluble polymers that do not have the crystallinity of cellulose. On the other hand, carboxymethyl cellulose, which retains the crystallinity of cellulose and does not completely dissolve in water but partially maintains the fibrous shape, has better shape retention due to its shape, crystallinity, and other characteristics. It is expected that new effects such as high will be obtained.

However, carboxymethyl cellulose in which the crystallinity of cellulose remains tends to be inhomogeneous, and problems such as unstable dispersion and easy formation of lumps in water have been observed. Such a phenomenon was particularly remarkable when the degree of carboxymethyl substitution was lowered in order to retain the crystallinity of cellulose. This makes it difficult to uniformly introduce a small amount of carboxymethyl groups into the cellulose (ie, rather than in a local form that is clustered in one or several places), with the carboxymethyl groups being locally It is considered that the quality varies due to the fact that the dense part is easily dissolved in water, while the part with few carboxymethyl groups is not dissolved. Therefore, in order to obtain stable quality carboxymethyl cellulose that can be dispersed in an aqueous medium, it is considered that a certain degree of carboxymethyl substitution is required. However, when the degree of carboxymethyl substitution was 0.20 or more, it was difficult to maintain, for example, the crystallinity of cellulose type I at 50% or more.

As a result of diligent studies, the present inventors have discovered a method for producing carboxymethyl cellulose capable of increasing the degree of carboxymethyl substitution to 0.20 or more while maintaining the crystallinity of cellulose type I at 50% or more. Further, the carboxymethyl cellulose thus obtained having a degree of carboxymethyl substitution of 0.20 or more, a degree of crystallization of cellulose type I of 50% or more, and a median diameter of 10.0 to 150.0 μm is an aqueous medium. When added to a mixture of oil-based medium and agitated with a stirring force (rotation speed 1000 to 15,000 rpm) equivalent to that of a household mixer, emulsification of the aqueous medium and oil-based medium is promoted and stable for a long period of time. It was found that an emulsion (that is, an aqueous medium and an oil-based medium are difficult to separate for a long period of time) can be formed.

The present invention includes, but is not limited to, the following.
[1] An emulsifier containing carboxymethyl cellulose having a degree of carboxymethyl substitution of 0.20 or more, a degree of crystallinity of cellulose type I of 50% or more, and a median diameter of 10.0 to 150.0 μm.
[2] The emulsifier according to [1], wherein the degree of carboxymethyl substitution in carboxymethyl cellulose is 0.50 or less.
[3] Carboxymethyl cellulose is produced by carrying out a mercerization reaction under a solvent mainly containing water, and then carrying out a carboxymethylation reaction under a mixed solvent of water and an organic solvent. [1] ] Or the emulsifier according to [2].
[4] The emulsifier according to [3], wherein the solvent mainly containing water is a solvent containing more than 50% by mass of water.
[5] The emulsifier according to [3] or [4], wherein the ratio of the organic solvent in the mixed solvent is 50 to 99% by mass with respect to the total of water and the organic solvent.
[6] The emulsifier according to any one of [1] to [5], which further comprises an aqueous medium.
[7] A food or drink containing the emulsifier according to any one of [1] to [6].
[8] A cosmetic product containing the emulsifier according to any one of [1] to [6].
[9] A coating material containing the emulsifier according to any one of [1] to [6].
[10] A step of adding the emulsifier according to any one of [1] to [6] to a mixture of an aqueous medium and an oil-based medium to prepare a mixture of the emulsifier, the aqueous medium, and an oil-based medium. , And the step of stirring the mixture of the emulsifier, the aqueous medium, and the oil-based medium to prepare an emulsion in which the aqueous medium and the oil-based medium are emulsified.
A method for producing an emulsion, including.
[11] In the step of preparing a mixture of the emulsifier, the aqueous medium, and the oil-based medium, the emulsifier is added so that the solid content of carboxymethyl cellulose in the emulsion is 0.05 to 1.00% by mass. The method for producing an emulsion according to [10], which comprises the above.
[12] The method for producing an emulsion according to [11] or [12], which comprises performing stirring at a rotation speed of 1000 to 15000 rpm for 1 minute or more in the step of preparing the emulsion.

The emulsifier of the present invention has stable quality even though the crystallinity of cellulose type I remains, and is a stable emulsion when added to a mixture of an aqueous medium and an oil medium, stirred and mixed. Can promote the formation of. It can be said that it is suitable for use as an emulsifier in various fields that require the formation of emulsions, for example, but not limited to these, in fields such as foods, cosmetics, and paints.

<Carboxymethyl cellulose>
The present invention relates to an emulsifier containing carboxymethyl cellulose having a carboxymethyl substitution degree of 0.20 or more, a cellulose type I crystallinity of 50% or more, and a median diameter of 10.0 to 150.0 μm.

Carboxymethyl cellulose has a structure in which some of the hydroxyl groups in the glucose residues constituting the cellulose are ether-bonded to the carboxymethyl group. Carboxymethyl cellulose may be in the form of a salt, and the carboxymethyl cellulose used in the present invention also includes a salt of carboxymethyl cellulose. Examples of the salt of carboxymethyl cellulose include metal salts such as sodium carboxymethyl cellulose salt.

<Degree of carboxymethyl substitution>
The carboxymethyl cellulose used in the present invention has a carboxymethyl substitution degree of 0.20 or more per anhydrous glucose unit of cellulose. Preferably, the degree of carboxymethyl substitution is 0.23 or more. If the degree of carboxymethyl substitution is less than 0.20, it is difficult to form a uniform emulsion due to precipitation or aggregation when added to a mixture of an aqueous medium and an oil medium. The upper limit of the carboxymethyl substitution degree is preferably 0.50 or less, more preferably 0.40 or less. If the degree of carboxymethyl substitution exceeds 0.50, dissolution in an aqueous medium is likely to occur, the fiber morphology cannot be maintained, and the emulsification promoting effect and the emulsion stabilizing effect may be reduced. In addition, the particle size cannot be measured in an aqueous medium. Therefore, the degree of carboxymethyl substitution is preferably in the range of 0.20 or more and 0.50 or less. In the range of 0.20 or more and 0.50 or less, it was particularly difficult to obtain carboxymethyl cellulose having a crystallinity of cellulose type I described later of 50% or more by the conventional water medium method. The inventors have stated that carboxymethyl cellulose having a carboxymethyl substitution degree of 0.20 or more and 0.50 or less, a cellulose type I crystallinity of 50% or more, and stable quality can be produced by, for example, a production method described later. I found it. The degree of carboxymethyl substitution can be adjusted by controlling the amount of the carboxymethylating agent to be reacted, the amount of the mercerizing agent, the composition ratio of water and the organic solvent, and the like.

In the present invention, the anhydrous glucose unit means individual anhydrous glucose (glucose residue) constituting cellulose. The degree of carboxymethyl substitution (also referred to as the degree of etherification) is the ratio of hydroxyl groups in glucose residues constituting cellulose that are substituted with carboxymethyl ether groups (carboxymethyl per glucose residue). The number of ether groups) is shown. The degree of carboxymethyl substitution may be abbreviated as DS.

The method for measuring the degree of carboxymethyl substitution is as follows:
Weigh approximately 2.0 g of the sample and place it in an Erlenmeyer flask with a 300 mL stopper. 100 mL of methanol nitrate (a solution of 1000 mL of methanol plus 100 mL of special grade concentrated nitric acid) is added and shaken for 3 hours to convert the salt of carboxymethylated cellulose (CMC) into H-CMC (hydrogen-type carboxymethylated cellulose). Weigh 1.5 to 2.0 g of the absolutely dry H-CMC and place it in an Erlenmeyer flask with a 300 mL stopper. Wet H-CMC with 15 mL of 80% methanol, add 100 mL of 0.1N-NaOH, and shake at room temperature for 3 hours. Using phenolphthalein as an indicator, excess NaOH is back titrated with 0.1 N-H ₂ SO ₄ , and the degree of carboxymethyl substitution (DS value) is calculated by the following formula.
A = [(100 x F'-0.1N-H ₂ SO ₄ (mL) x F) x 0.1] / (absolute dry mass (g) of H-CMC)
Carboxymethyl substitution degree = 0.162 × A / (1 to 0.058 × A)
F': 0.1N-H ₂ SO ₄ factor F: 0.1N-NaOH factor.

<Crystallinity of cellulose type I>
The crystallinity of cellulose type I in carboxymethyl cellulose used in the present invention is 50% or more. Preferably, the crystallinity is 60% or more. If the crystallinity of cellulose type I is less than 50%, the desired emulsion promoting effect cannot be obtained. The crystallinity of cellulose can be controlled by the concentration of the mercerizing agent, the temperature during treatment, and the degree of carboxymethylation. Since a high concentration of alkali is used in mercerization and carboxymethylation, type I crystals of cellulose are easily converted to type II, but they are modified by adjusting the amount of alkali (mercerizing agent) used. By adjusting the degree, the desired crystallinity can be maintained. The upper limit of the crystallinity of cellulose type I is not particularly limited. In reality, about 90% is considered to be the upper limit.

The method for measuring the crystallinity of cellulose type I of carboxymethylated pulp is as follows:
The sample is placed on a glass cell and measured using an X-ray diffraction measuring device (LabX XRD-6000, manufactured by Shimadzu Corporation). The crystallinity is calculated by using a method such as Segal, and the diffraction intensity of the 002 surface of 2θ = 22.6 ° and 2θ = are based on the diffraction intensity of 2θ = 10 ° to 30 ° in the X-ray diffraction diagram. It is calculated by the following formula from the diffraction intensity of the amorphous portion of 18.5 °.

Xc = (I002c-Ia) / I002c × 100
Xc = Cellulose type I crystallinity (%)
I002c: 2θ = 22.6 °, diffraction intensity of 002 surface Ia: 2θ = 18.5 °, diffraction intensity of amorphous part.

Carboxymethyl cellulose is generally obtained by treating cellulose with an alkali (mercerization) and then reacting the obtained mercerized cellulose (also referred to as alkali cellulose) with a carboxymethylating agent (also referred to as an etherifying agent). Can be manufactured.

<Median diameter>
The carboxymethyl cellulose used in the present invention has a median diameter of 10.0 to 150.0 μm. It is preferably 25.0 to 100.0 μm, more preferably 35.0 to 70.0 μm. If the median diameter is less than 10.0 μm, it is difficult to handle because the powder is fluttering because it is fine powder, and if it exceeds 150.0 μm, it becomes bulky and the powder packing work is difficult, which is not preferable. Furthermore, when the median diameter is within the above range, the fiber length and fiber diameter of carboxymethyl cellulose are not too thin and are maintained within a certain range, and it is easy to exhibit a good emulsification promoting effect and long-term stability of the emulsion. It is presumed to be. The median diameter of carboxymethyl cellulose can be adjusted by grinding carboxymethyl cellulose wet or dry.

The median diameter can be measured by the following procedure:
Using methanol as the dispersion medium, prepare a sample so that the scattering intensity is 0.1 to 20%, and measure the sample with a laser diffraction type particle size distribution measuring device (Malburn Co., Ltd., Mastersizer 3000).

<Viscosity>
The carboxymethyl cellulose used in the present invention preferably has a high viscosity in water. In the present specification, the method for measuring viscosity is as follows:
A dispersion using water containing a predetermined concentration of carboxymethyl cellulose as a dispersion medium is prepared. Stir at 600 rpm for 3 hours using a stirrer at 25 ° C. Then, according to the method of JIS-Z-8803, the viscosity after 3 minutes is measured at a predetermined rotation speed using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.).

When the solid content of carboxymethyl cellulose used in the emulsifier of the present invention is 1% (w / v) (dispersion medium: water), the viscosity (25 ° C.) at 6 rpm is 1000 mPa · s to 30,000 mPa · s. It is preferable, 2000 mPa · s to 25,000 mPa · s is more preferable, and 2500 mPa · s to 20000 mPa · s is further preferable. The viscosity (25 ° C.) at a rotation speed of 60 rpm is preferably 100 mPa · s to 10000 mPa · s, more preferably 300 mPa · s to 5000 mPa · s, and even more preferably 500 mPa · s to 4000 mPa · s.

<Degree of anionization>
The carboxymethyl cellulose used in the present invention preferably has an anionization degree (also referred to as anion charge density) of 0.00 meq / g or more and 1.00 meq / g or less. The method for measuring the degree of anionization is as follows:
Carboxymethyl cellulose is dispersed in water to prepare an aqueous dispersion having a solid content of 10 g / L, and the mixture is stirred with a magnetic stirrer at 1000 rpm for a whole day and night. After diluting the obtained slurry to 0.1 g / L, 10 ml was sampled, titrated with a 1/1000 normal diallyldimethylammonium chloride (DADMAC) using a flow current detector (Mutek Particle Charge Detector 03), and flowed. Using the amount of DADMAC added until the current becomes zero, calculate the degree of anionization by the following formula:
q = (V × c) / m
q: Degree of anionization (meq / g)
V: Addition amount (L) of DADMAC until the flow current becomes zero
c: DADMAC concentration (meq / L)
m: Mass (g) of carboxymethylated pulp in the measurement sample.

In the present specification, the "degree of anionization" corresponds to the equivalent amount of DADMAC required to neutralize an anionic group in a unit mass of carboxymethyl cellulose, as can be seen from the above measurement method, and has a unit mass of carboxymethyl cellulose. Corresponds to the equivalent of anions per carboxymethyl cellulose.

The degree of anionization of carboxymethyl cellulose is preferably 0.00 meq / g or more and 1.00 meq / g or less, more preferably 0.00 meq / g or more and 0.80 meq / g or less, and 0.00 meq / g or more and 0. More preferably, it is 60 meq / g or less. In carboxymethyl cellulose having a degree of anionization in such a range, the carboxymethyl group is introduced uniformly throughout the cellulose rather than locally, as compared with carboxymethyl cellulose having a degree of anionization higher than 1.00 meq / g. It is considered that the effect of the present invention can be obtained more stably. Carboxymethyl cellulose having such an anionization degree can be produced, for example, by a method described later.

<Ratio of filtration residue>
The carboxymethyl cellulose used in the present invention preferably has a small amount of lumps (lumps) formed when water is used as a dispersion medium (aqueous dispersion) (that is, a small proportion of filtration residues is formed). Specifically, carboxymethyl cellulose was added to 500 g of water, stirred at 400 rpm for 5 seconds, and then naturally filtered using a 20-mesh filter. The dry mass of the filtration residue on the filter was the dry mass of the filtration residue added to the water. It is preferably 0 to 30% by mass based on the dry mass of the above (in the present specification, the dry mass of the filtration residue after natural filtration with respect to the dry mass of carboxymethyl cellulose added to water calculated by the above method. The proportion is referred to as the "percentage of filtration residue"). Specific methods for measuring the proportion of filtration residue are as follows:
(1) Measurement of the amount of filtration residue 500 g of water is collected in a 1 L beaker. Divide 5 g of carboxymethyl cellulose and record the mass (mass of carboxymethyl cellulose). A stirring blade is set in a stirrer (IKA (registered trademark) EUROSTAR PCV S1 (manufactured by IKA)), and water is stirred at 400 rpm. Carboxymethyl cellulose whose mass has been recorded is added to the stirring water at once, and the mixture is stirred for 5 seconds after the addition. After stirring is completed, turn off the power of the stirrer. After the stirring is completed, natural filtration is quickly performed using a 20-mesh filter whose mass has been measured in advance. After natural filtration, both the filter and the residue on it are dried on a vat at 100 ° C. for 2 hours. The absolute dry mass (g) of the residue is calculated by measuring the mass of the filter and the residue on it and subtracting the mass of the filter (absolute dry residue mass).
(2) Calculation of Moisture Content of Carboxymethyl Cellulose The weighing bottle is heated at 100 ° C. for 2 hours, cooled in a desiccator containing silica gel, and the absolute dry mass of the weighing bottle is precisely weighed (absolute dry weighing bottle mass). Weigh about 1.5 g of carboxymethyl cellulose in a weighing bottle and weigh it precisely (CMC mass before drying). Open the lid of the weighing bottle and heat to dry at 105 ° C. for 2 hours. Close the lid of the weighing bottle and cool in a desiccator containing silica gel for 15 minutes. The mass of the weighing bottle after drying (including the carboxymethyl cellulose after drying) is precisely weighed (the mass of the weighing bottle containing CMC after drying). Calculate the water content of carboxymethyl cellulose using the following formula:
Moisture (%) of carboxymethyl cellulose = [{CMC mass before drying (g)-(mass of weighing bottle containing CMC after drying (g) -mass of absolute dry weighing bottle (g))} / mass of CMC before drying (g)] × 100.
(3) Calculation of the ratio of filtered residue Using the mass (g) of carboxymethylated cellulose and the mass of absolute dry residue (g) measured in (1), and the water content (%) of carboxymethyl cellulose calculated in (2). , Calculate the proportion of carboxymethyl cellulose filtration residue by the following formula:
Percentage of filtration residue of carboxymethyl cellulose (%) = [mass of absolute dry residue (g) / {mass of carboxymethyl cellulose (g) x (water content of 100-carboxymethyl cellulose (%)) / 100}] x 100.

The ratio of the filtration residue of carboxymethyl cellulose calculated by the above formula is preferably 0 to 30%, more preferably 0 to 20%, still more preferably 0 to 10%. Carboxymethyl cellulose, which has a small proportion of filtration residue, is easy to disperse and has excellent handleability. Carboxymethyl cellulose having a small proportion of such filtration residue can be produced, for example, by the method described later.

<Shopper Rigra Water Degree>
The carboxymethyl cellulose used in the present invention preferably has a shopper-ligula freeness of 60.0 ° SR or higher. The method for measuring the freeness of shopper / leaguer is based on JISP 82121-1: 2012, and specifically, it is as follows:
Carboxymethyl cellulose is dispersed in water to prepare an aqueous dispersion having a solid content of 10 g / L, and the mixture is stirred with a magnetic stirrer at 1000 rpm for a whole day and night. The resulting slurry is diluted to 1 g / L. A 60 mesh screen (wire thickness 0.17 mm) was set on DFR-04 manufactured by Mutec, and the amount of liquid passing through the mesh was measured for 60 seconds from 1000 ml of the test solution, and according to JISP 812-1: 2012. Calculate the Shopper-Regula free water content by the above method.

The Shopper-Leigler filtrate is a measure of the degree of drainage of the fiber suspension, the lower limit is 0 ° SR, the upper limit is 100 ° SR, and the shopper-Leiger filtrate is 100 ° SR. The closer to, the smaller the drainage (drainage amount), that is, the higher the water retention of the fiber.

The shopper-ligula freeness of carboxymethyl cellulose is preferably 60.0 ° SR or higher, and more preferably 65.0 ° SR or higher. The upper limit is not particularly limited, but is 100.0 ° SR or less, preferably 90.0 ° SR or less. Shopper-Regula Carboxymethyl cellulose having a free water content of 60.0 ° SR or higher has high water retention, and is, for example, not limited to these, in various compositions such as foods and drinks, cosmetics, paints, and pharmaceuticals. It is thought that the effect of Carboxymethyl cellulose having such a shopper-ligula freeness can be produced, for example, by the method described later.

<Canadian Standard Freeness>
The carboxymethyl cellulose used in the present invention preferably has a Canadian standard freeness (Canadian standard drainage degree) of 150 ml or less, more preferably 120 ml or less, and even more preferably 110 ml or less. Carboxymethyl cellulose having such Canadian standard freedom can be produced, for example, by the method described later. The Canadian standard freeness measures the degree of drainage of the fiber suspension, and the smaller the value, the smaller the drainage (displacement), that is, the higher the water retention of the fiber. The measurement method of Canadian Standard Freeness is as follows:
Prepare a sample by the same method as the above-mentioned shopper-rigra drainage degree, set a 60 mesh screen (wire thickness 0.17 mm) on DFR-04 manufactured by Mutec, and apply the above mesh from 1000 ml of the test solution. The amount of liquid passing through is measured for 60 seconds, and the Canadian standard freeness is calculated by a method according to JISP 8121-2: 2012.

<Amount of drainage>
The amount of filtered water of the carboxymethyl cellulose used in the present invention is preferably 400 ml or less, more preferably 380 ml or less, still more preferably 370 ml or less. Carboxymethyl cellulose having such a drainage amount can be produced, for example, by the method described later. The amount of drained water measures the degree of drainage of the fiber suspension, and the smaller the value, the smaller the drainage (displacement), that is, the higher the water retention of the fiber. The method for measuring the amount of drained water is as follows:
Prepare the sample by the same method as the above-mentioned shopper-rigra drainage degree, set a 60 mesh screen (wire thickness 0.17 mm) on DFR-04 manufactured by Mutec, and apply the above mesh from 1000 ml of the test solution. The amount of liquid passing through was measured for 60 seconds, and the amount of filtered water was calculated.

<Manufacturing method of carboxymethyl cellulose>
Carboxymethyl cellulose is generally obtained by treating cellulose with an alkali (mercerization) and then reacting the obtained mercerized cellulose (also referred to as alkali cellulose) with a carboxymethylating agent (also referred to as an etherifying agent). Can be manufactured. As a general method for producing carboxymethyl cellulose, there are a water medium method in which both marcellation and carboxymethylation are carried out using water as a solvent, and a solvent in which both marcelation and carboxymethylation are carried out mainly in an organic solvent. The solvent method, which is a method to be carried out, is known. On the other hand, the carboxymethyl cellulose having a specific degree of carboxymethyl substitution and a degree of crystallization of cellulose type I used in the present invention is not limited to this, but for example, a solvent mainly containing water for mercerization (alkali treatment of cellulose). It can be produced by performing it below and then performing carboxymethylation (also referred to as etherification) under a mixed solvent of water and an organic solvent. The carboxymethyl cellulose obtained in this manner maintains a high crystallinity of cellulose type I while setting the degree of carboxymethyl substitution to 0.20 or more, which is difficult to achieve with the carboxymethyl cellulose obtained by the conventional water medium method or solvent method. It has the characteristic of

<Cellulose>
As used herein, cellulose means a polysaccharide having a structure in which D-glucopyranose (simply referred to as “glucose residue” or “anhydrous glucose”) is linked by β-1,4 bonds. Cellulose is generally classified into natural cellulose, regenerated cellulose, fine cellulose, microcrystalline cellulose excluding non-crystalline regions, etc., based on the origin, manufacturing method, and the like. In the present invention, any of these celluloses can be used as a raw material for mercerized cellulose, but in order to maintain a crystallinity of cellulose type I of 50% or more in carboxymethyl cellulose, crystallization of cellulose type I It is preferable to use cellulose having a high degree as a raw material. The crystallinity of cellulose type I of the raw material cellulose is preferably 70% or more, and more preferably 80% or more. The method for measuring the crystallinity of cellulose type I is as described above.

Examples of natural cellulose include bleached pulp or unbleached pulp (bleached wood pulp or unbleached wood pulp); linters, purified linters; cellulose produced by microorganisms such as acetic acid bacteria. The raw material of bleached pulp or unbleached pulp is not particularly limited, and examples thereof include wood, cotton, straw, bamboo, hemp, jute, and kenaf. Further, the method for producing bleached pulp or unbleached pulp is not particularly limited, and a mechanical method, a chemical method, or a method in which the two are combined may be used. The bleached pulp or unbleached pulp classified according to the production method includes, for example, mechanical pulp (thermomechanical pulp (TMP), crushed wood pulp), chemical pulp (conifer unbleached sulphite pulp (NUSP), conifer bleached sulphite pulp (NBSP). ) And the like, unbleached coniferous kraft pulp (NUKP), bleached coniferous kraft pulp (NBKP), unbleached broadleaf kraft pulp (LUKP), kraft pulp such as broadleaf bleached kraft pulp (LBKP)) and the like. Further, dissolved pulp may be used in addition to the pulp for papermaking. Dissolving pulp is chemically refined pulp, which is mainly dissolved in chemicals and used as a main raw material for artificial fibers, cellophane, and the like.

Examples of the regenerated cellulose include those obtained by dissolving cellulose in a solvent such as a cuprammonium solution, a cellulose zantate solution, or a morpholine derivative, and spinning it again. The fine cellulose is obtained by subjecting a cellulosic material such as the above-mentioned natural cellulose or regenerated cellulose to a depolymerization treatment (for example, acid hydrolysis, alkali hydrolysis, enzymatic decomposition, blasting treatment, vibration ball mill treatment, etc.). Examples thereof include those obtained by mechanically processing the cellulosic material.

<Mercerization>
The above-mentioned cellulose is used as a raw material, and mercerized cellulose (also referred to as alkaline cellulose) is obtained by adding a mercerizing agent (alkali). According to the method described herein, water is mainly used as the solvent in this marcelation reaction, and a mixed solvent of an organic solvent and water is used in the next carboxymethylation to obtain a specific degree of carboxymethyl substitution. And carboxymethyl cellulose having both the degree of crystallization of cellulose type I can be economically obtained.

The term "water-based solvent" as a solvent mainly uses water means a solvent containing water in a proportion higher than 50% by mass. The water in the solvent mainly containing water is preferably 55% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass or more. It is more preferably 90% by mass or more, and further preferably 95% by mass or more. Particularly preferably, the solvent mainly containing water is 100% by mass (that is, water) of water. The higher the proportion of water during mercerization, the more the advantage is that the carboxymethyl groups are uniformly introduced by the cellulose. Examples of the solvent other than water (used by mixing with water) in the solvent mainly containing water include an organic solvent used as a solvent in the subsequent carboxymethylation. For example, alcohols such as methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol and tertiary butanol, ketones such as acetone, diethyl ketone and methyl ethyl ketone, and dioxane, diethyl ether, benzene and dichloromethane. And the like, these alone or a mixture of two or more kinds can be added to water in an amount of less than 50% by mass and used as a solvent for marcel formation. The organic solvent in the solvent mainly containing water is preferably 45% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, still more preferably 20% by mass or less. , More preferably 10% by mass or less, further preferably 5% by mass or less, and even more preferably 0% by mass.

Examples of the mercerizing agent include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, and any one or a combination of two or more of these can be used. The mercerizing agent is not limited to this, but these alkali metal hydroxides are used in the reactor as an aqueous solution of, for example, 1 to 60% by mass, preferably 2 to 45% by mass, and more preferably 3 to 25% by mass. Can be added.

The amount of the marcel agent used is not particularly limited as long as it can achieve both a carboxymethyl substitution degree of 0.20 or more in carboxymethyl cellulose and a crystallization degree of cellulose type I of 50% or more, but in one embodiment, 100 g of cellulose is used. It is preferably 0.1 mol or more and 2.5 mol or less, more preferably 0.3 mol or more and 2.0 mol or less, and 0.4 mol or more and 1.5 mol or less with respect to (absolute drying). Is more preferable.

The amount of the solvent mainly containing water at the time of mercerization is not particularly limited as long as it can be stirred and mixed with the raw materials, but is preferably 1.5 to 20 times by mass with respect to the cellulose raw material, and 2 to 10 times. It is more preferable that the mass is multiplied.

In the mercerization treatment, the bottoming material (cellulose) and a solvent mainly composed of water are mixed, and the temperature of the reactor is adjusted to 0 to 70 ° C., preferably 10 to 60 ° C., more preferably 10 to 40 ° C. Then, an aqueous solution of the mercerizing agent is added, and the mixture is stirred for 15 minutes to 8 hours, preferably 30 minutes to 7 hours, more preferably 30 minutes to 3 hours. This gives mercerized cellulose (alkaline cellulose).

The pH at the time of mercerization is preferably 9 or more, whereby the mercerization reaction can proceed. The pH is more preferably 11 or more, still more preferably 12 or more, and may be 13 or more. The upper limit of pH is not particularly limited.

Mercerization can be carried out using a reactor capable of mixing and stirring each of the above components while controlling the temperature, and various reactors conventionally used for the mercerization reaction can be used. For example, a batch type agitator in which two shafts agitate and each of the above components is mixed is preferable from the viewpoint of both uniform mixing property and productivity.

<Carboxymethylation>
Carboxymethyl cellulose is obtained by adding a carboxymethylating agent (also referred to as an etherifying agent) to mercerized cellulose. According to the method described herein, water is used as the main solvent for marcel formation, and a mixed solvent of water and an organic solvent is used for carboxymethylation to obtain a specific degree of carboxymethyl substitution. And carboxymethyl cellulose having both the degree of crystallization of cellulose type I can be economically obtained.

Examples of the carboxymethylating agent include monochloroacetic acid, sodium monochloroacetic acid, methyl monochloroacetic acid, ethyl monochloroacetic acid, isopropyl monochloroacetate and the like. Of these, monochloroacetic acid or sodium monochloroacetate is preferable in terms of availability of raw materials.

The amount of the carboxymethylating agent used is not particularly limited as long as it can achieve both a carboxymethyl substitution degree of 0.20 or more in carboxymethyl cellulose and a crystallinity of cellulose type I of 50% or more, but in one embodiment, cellulose is used. It is preferable to add in the range of 0.5 to 1.5 mol per anhydrous glucose unit. The lower limit of the above range is more preferably 0.6 mol or more, further preferably 0.7 mol or more, and the upper limit is more preferably 1.3 mol or less, still more preferably 1.1 mol or less. The carboxymethylating agent can be added to the reactor as an aqueous solution of, for example, 5 to 80% by mass, more preferably 30 to 60% by mass, without limitation, and is added in a powder state without being dissolved. You can also do it.

The molar ratio of the mercelling agent to the carboxymethylating agent (merselling agent / carboxymethylating agent) is generally 0.99 to 2.45 when monochloroacetic acid or sodium monochloroacetic acid is used as the carboxymethylating agent. Will be adopted by. The reason is that if it is less than 0.90, the carboxymethylation reaction may be insufficient, and unreacted monochloroacetic acid or sodium monochloroacetate may remain, resulting in waste, and 2.45. If the amount exceeds the above, a side reaction between the excess marcel agent and monochloroacetic acid or sodium monochloroacetic acid may proceed to form an alkali metal glycolic acid salt, which may be uneconomical.

In carboxymethylation, the effective utilization rate of the carboxymethylating agent is preferably 15% or more. It is more preferably 20% or more, further preferably 25% or more, and particularly preferably 30% or more. The effective utilization rate of the carboxymethylating agent refers to the ratio of the carboxymethyl group introduced into cellulose among the carboxymethyl groups in the carboxymethylating agent. By using a solvent mainly composed of water for marcel formation and using a mixed solvent of water and an organic solvent for carboxymethylation, a high effective utilization rate of the carboxymethylating agent (that is, a carboxymethylating agent) The carboxymethyl cellulose used in the present invention can be obtained economically without significantly increasing the amount of the solvent used. The upper limit of the effective utilization rate of the carboxymethylating agent is not particularly limited, but in reality, the upper limit is about 80%. The effective utilization rate of the carboxymethylating agent may be abbreviated as AM.

The method for calculating the effective utilization rate of the carboxymethylating agent is as follows:
AM = (DS x number of moles of cellulose) / number of moles of carboxymethylating agent DS: degree of carboxymethyl substitution (measurement method will be described later)
Number of moles of cellulose: Pulp mass (dry mass when dried at 100 ° C. for 60 minutes) / 162
(162 is the molecular weight of cellulose per glucose unit).

The concentration of the cellulose raw material in the carboxymethylation reaction is not particularly limited, but is preferably 1 to 40% (w / v) from the viewpoint of increasing the effective utilization rate of the carboxymethylating agent.

At the same time as the addition of the carboxymethylating agent, or immediately before or after the addition of the carboxymethylating agent, an organic solvent or an aqueous solution of the organic solvent is appropriately added to the reactor, or water other than the water used for the marcelification treatment by reducing the pressure or the like The organic solvent and the like of the above are appropriately reduced to form a mixed solvent of water and the organic solvent, and the carboxymethylation reaction is allowed to proceed under the mixed solvent of the water and the organic solvent. The timing of addition or reduction of the organic solvent may be between the end of the mercerization reaction and immediately after the addition of the carboxymethylating agent, and is not particularly limited, but for example, 30 minutes before and after the addition of the carboxymethylating agent. Within is preferable.

Examples of the organic solvent include alcohols such as methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol and tertiary butanol, ketones such as acetone, diethyl ketone and methyl ethyl ketone, and dioxane and diethyl ether. Examples thereof include benzene and dichloromethane, and these alone or a mixture of two or more thereof can be added to water and used as a solvent for carboxymethylation. Of these, monohydric alcohols having 1 to 4 carbon atoms are preferable, and monohydric alcohols having 1 to 3 carbon atoms are more preferable because of their excellent compatibility with water.

The ratio of the organic solvent in the mixed solvent at the time of carboxymethylation is preferably 20% by mass or more, more preferably 30% by mass or more, based on the total amount of water and the organic solvent. , 40% by mass or more, more preferably 45% by mass or more, and particularly preferably 50% by mass or more. The higher the proportion of the organic solvent, the more likely it is that uniform substitution of carboxymethyl groups will occur, and the advantage of obtaining stable quality carboxymethyl cellulose can be obtained. The upper limit of the proportion of the organic solvent is not limited and may be, for example, 99% by mass or less. Considering the cost of the organic solvent to be added, it is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, still more preferably 70% by mass or less.

The reaction medium for carboxymethylation (a mixed solvent of water and an organic solvent that does not contain cellulose) has a smaller proportion of water than the reaction medium for mercerization (in other words, the proportion of the organic solvent is higher). Many) is preferable. By satisfying this range, it becomes easy to maintain the crystallinity of the obtained carboxymethyl cellulose, and the carboxymethyl cellulose used in the present invention can be obtained more efficiently. In addition, when the reaction medium for carboxymethylation has a smaller proportion of water (more proportion of organic solvent) than the reaction medium for mercerization, the transition from the mercerization reaction to the carboxymethylation reaction occurs. Another advantage is that a mixed solvent for the carboxymethylation reaction can be formed by a simple means of adding a desired amount of an organic solvent to the reaction system after the completion of the mercerization reaction.

After forming a mixed solvent of water and an organic solvent and adding a carboxymethylating agent to the mercerized cellulose, the temperature is preferably kept constant in the range of 10 to 40 ° C. for 15 minutes to 4 hours, preferably 15 Stir for about 1 minute to 1 hour. The mixing of the liquid containing mercerized cellulose and the carboxymethylating agent is preferably carried out in a plurality of times or by dropping in order to prevent the reaction mixture from becoming hot. After adding the carboxymethylating agent and stirring for a certain period of time, the temperature is raised if necessary, and the reaction temperature is set to 30 to 90 ° C., preferably 40 to 90 ° C., more preferably 60 to 80 ° C. for 30 minutes to The etherification (carboxymethylation) reaction is carried out for 10 hours, preferably 1 to 4 hours to obtain carboxymethyl cellulose. By raising the temperature during the carboxymethylation reaction, there is an advantage that the etherification reaction can be efficiently carried out in a short time.

In the case of carboxymethylation, the reactor used for mercerization may be used as it is, or another reactor capable of mixing and stirring each of the above components while controlling the temperature may be used. ..

After completion of the reaction, the remaining alkali metal salt may be neutralized with a mineral acid or an organic acid. Further, if necessary, the by-produced inorganic salts, organic acid salts and the like may be removed by washing with hydrous methanol. Then, the carboxymethyl cellulose is dried and classified to obtain carboxymethyl cellulose having a predetermined median diameter, and pulverization (wet pulverization or dry pulverization) may be performed before or after the drying. Examples of the apparatus used in the wet pulverization include apparatus such as a homogenizer, a mascoroider, and a pearl mill. Examples of the device used for dry pulverization include impact mills such as hammer mills and pin mills, medium mills such as ball mills and tower mills, and jet mills.

<Emulsifier>
The emulsifier of the present invention contains the above-mentioned carboxymethyl cellulose having a degree of carboxymethyl substitution of 0.20 or more, a degree of crystallinity of cellulose type I of 50% or more, and a median diameter of 10.0 to 150.0 μm. .. The emulsifier is an agent having an action of promoting emulsification of an aqueous medium and an oil-based medium and stabilizing emulsification when the mixture is added to a mixture of an aqueous medium and an oil-based medium, stirred and mixed. .. When an agent "promotes emulsification", it means that emulsification can be formed in the presence of the agent with less energy (less rotation speed of the mixer, less processing time, etc.) than in the absence of the agent. Also, the agent "stabilizes emulsification" means that the emulsion is retained in the presence of the agent for a longer period of time without separation into the aqueous medium and the oil-based medium than in the absence of the agent. To say that.

The emulsifier may be in a solid form such as powder or pellet, or may be in a water-containing form such as liquid or gel. When the emulsifier is in solid form, the emulsifier may be the carboxymethyl cellulose itself described above (ie, 100% by weight of the emulsifier may consist of the carboxymethyl cellulose described above) to the carboxymethyl cellulose described above. In addition, it may contain dyes, excipients and the like. When the emulsifier is in the solid form, the above-mentioned carboxymethyl cellulose preferably occupies 50% by mass or more, more preferably 80% by mass or more, and further preferably 95% by mass or more. Also, as described above, it may be 100% by mass.

When the emulsifier is in a liquid or gel form, the emulsifier preferably further contains an aqueous medium in addition to the above-mentioned carboxymethyl cellulose, and the carboxymethyl cellulose is preferably dispersed or suspended in the aqueous medium. .. The aqueous medium refers to water and a water-soluble organic solvent that can be mixed with water in an arbitrary ratio, and specifically, water, methanol, ethanol, isopropanol, isobutanol, sec-butanol, tert-butanol, methyl. Cellosolve, ethyl cellosolve, ethylene glycol, glycerin, ethylene glycol dimethyl ether, 1,4-dioxane, tetrahydrofuran, acetone, methyl ethyl ketone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, and two or more of these. A mixture can be mentioned. Preferably, the aqueous medium is water.

When the emulsifier contains an aqueous medium, the concentration of the above-mentioned carboxymethyl cellulose in the emulsifier (including the aqueous medium) is preferably 0.1 to 5.0% (w / v), and is 0.2 to 5.0%. It is more preferably 3.0% (w / v), and even more preferably 0.3 to 2.0% (w / v). When carboxymethyl cellulose and an aqueous medium are mixed to form an emulsifier, carboxymethyl cellulose and an aqueous medium are mixed so that the concentration of carboxymethyl cellulose is within the above range, and the mixture is stirred using an arbitrary stirring device. It is preferable to disperse or suspend carboxymethyl cellulose in an aqueous medium.

When the emulsifier contains an aqueous medium, the emulsifier may take a liquid or gel form, of which liquid (carboxymethyl cellulose is suspended in the aqueous medium and the whole is solidified into a gel). It is more preferable to have fluidity). If the emulsifier is in the form of a gel, when it is added to a mixture of an aqueous medium and an oil-based medium to be emulsified, the emulsifier may settle and may not mix well. Therefore, when the emulsifier contains an aqueous medium, the amount of carboxymethyl cellulose in the emulsifier is set to such an amount that the emulsifier does not gel, and the carboxymethyl cellulose and the aqueous medium are stirred with such a stirring force that the emulsifier does not gel. And are preferably mixed. For example, but not limited to this, when water is used as an aqueous medium, the solid content of carboxymethyl cellulose in water is 0.5% (w / v), and the mixture is stirred and mixed with a mixer at a rotation speed of 10500 rpm for 5 minutes to obtain carboxymethyl cellulose. Can produce a liquid (non-gelled) emulsifier suspended in water. If the mixture is stirred and mixed for 10 minutes under the same conditions, it will gel.

The emulsifier of the present invention contains carboxymethyl cellulose having a stable quality while achieving a carboxymethyl substitution degree of 0.20 or more and a cellulose type I crystallinity of 50% or more, and having an appropriate median diameter. It is suitable as an emulsifier in various fields such as foods and drinks, cosmetics, paints, pharmaceuticals, feeds, and papermaking because it has good handleability, high emulsification promoting effect, and emulsion stabilizing effect. be able to.

The emulsifier of the present invention can be used by adding it to foods and drinks. Foods and drinks include, but are not limited to, dressings, mayonnaise, whipped cream and the like.
The emulsifier of the present invention can be used by adding it to cosmetics. Cosmetics include, but are not limited to, facial cleansers, hair wash products, hair styling products, lotions, creams, nails, and the like.

The emulsifier of the present invention can be used by adding it to a paint. In addition, it can be used by adding it to an emulsified product, for example, an ointment in a pharmaceutical product, a feed (for example, milk replacer for cows, etc.).

<Manufacturing method of emulsion>
By adding the emulsifier of the present invention to a mixture of an aqueous medium and an oil-based medium, stirring and mixing the mixture, the aqueous medium and the oil-based medium can be emulsified to produce an emulsion. The aqueous medium refers to water and a water-soluble organic solvent that can be mixed with water in an arbitrary ratio, and examples thereof are as described above in the “Emulsifier” column. An oil-based medium is a substance that is liquid (including highly viscous but fluid) at room temperature, which does not mix (separate) when added to water. The water-based medium and the oil-based medium may be independently one or a mixture of a plurality of substances. The mixing ratio of the aqueous medium to be emulsified and the oil-based medium is not particularly limited, and for example, the water-based medium: oil-based medium (mass ratio) may be in the range of 1:99 to 99: 1.

The ratio of the emulsifier added to the mixture of the water-based medium and the oil-based medium varies depending on the type of the water-based medium and the oil-based medium used, the mixing ratio of the water-based medium and the oil-based medium, and the like, and is not particularly limited. The emulsifier may be added in an amount such that the mass of the emulsifier-derived carboxymethyl cellulose is 0.01 to 5.00 mass% with respect to the mass of the mixture of the oil-based medium and the emulsifier (or the emulsion obtained from the mixture). It is more preferable to add the emulsifier in an amount of 0.02 to 3.00% by mass, and further preferably to add the emulsifier in an amount of 0.05 to 1.00% by mass. Stable emulsification for a long period of time (difficult to separate water-based medium and oil-based medium) by adding an emulsifier so that the amount of carboxymethyl cellulose is such an amount, depending on the type of mixture of water-based medium and oil-based medium. It is thought that things can be formed. When the amount of carboxymethyl cellulose is 1.00% by mass or less, there is an advantage that the generation of bubbles in the emulsion can be suppressed.

After the emulsifier is added to the mixture of the aqueous medium and the oil-based medium, the aqueous medium and the oil-based medium can be emulsified by using a known mixing, stirring, emulsifying, or dispersing device. Since the specific carboxymethyl cellulose used in the emulsifier of the present invention has good miscibility with an aqueous medium or an oil-based medium, stirring is about the same as that of a household juicer mixer without using a special device such as a high-pressure homogenizer. Emulsification can be formed by force. Examples of such a mixer include a mixer having a rotation speed of 1000 to 15000 rpm, preferably about 3000 to 12000 ppm, more preferably 5000 to 12000 rpm, and further preferably 6000 to 12000 rpm. Using such a mixer, stirring may be performed for 1 minute or longer, preferably about 2 to 15 minutes, more preferably about 3 to 10 minutes.

When a device such as a high-pressure homogenizer to which a strong shearing force is applied is used, the particle size of carboxymethyl cellulose tends to decrease, but when a mixer having a rotation speed of about 1000 to 15000 rpm is used, the particle size of carboxymethyl cellulose is large. Does not fluctuate. For example, the median diameter of carboxymethyl cellulose when the carboxymethyl cellulose used in the present invention is stirred in a medium at a rotation speed of 1000 to 15000 rpm is such that the median diameter of carboxymethyl cellulose before the stirring treatment is D _50A and after the stirring treatment. When the median diameter of carboxymethyl cellulose is D _50B ,
90 ≤ D _50B / D _50A x 100 ≤ 110
Satisfy the formula of.

The fact that the median diameter of carboxymethyl cellulose does not change much before and after the stirring treatment means that the carboxymethyl cellulose is not too finely divided in the emulsion, and it is considered that the emulsion stabilizing effect of the carboxymethyl cellulose is easily maintained, which is preferable. .. Therefore, it can be said that using a mixer having a rotation speed of about 1000 to 15000 rpm is one of the preferable embodiments. However, the emulsification is not limited to this, and emulsification may be performed using a device having a high shearing force such as a high-pressure homogenizer depending on the application.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Unless otherwise specified, parts and% indicate parts by mass and% by mass.

(Example 1)
When 20 parts of sodium hydroxide dissolved in 100 parts of water was added to a biaxial kneader whose rotation speed was adjusted to 100 rpm, and hardwood pulp (LBKP manufactured by Nippon Paper Industries Co., Ltd.) was dried at 100 ° C. for 60 minutes. 100 parts were charged by dry mass. Mercerized cellulose was prepared by stirring and mixing at 30 ° C. for 90 minutes. Further, 230 parts of isopropanol (IPA) and 60 parts of sodium monochloroacetate were added with stirring, and after stirring for 30 minutes, the temperature was raised to 70 ° C. and a carboxymethylation reaction was carried out for 90 minutes. The concentration of IPA in the reaction medium during the carboxymethylation reaction is 70%. After completion of the reaction, the reaction was neutralized with acetic acid to about pH 7, deliquesed, dried, and pulverized. Carboxymethyl cellulose having a carboxymethyl substitution degree of 0.24, a cellulose type I crystallinity of 71%, and a median diameter of 59.0 μm. Sodium salt was obtained. The methods for measuring the degree of carboxymethyl substitution, the degree of crystallinity of cellulose type I, and the median diameter are as described above.

The obtained sodium salt of carboxymethyl cellulose was added to water to adjust the solid content of carboxymethyl cellulose to 1% (w / v). The obtained mixture of carboxymethyl cellulose and water was stirred with a household juicer mixer (product name: mixer YM-B12D1 manufacturer: herb relax) at a rotation speed of 10500 rpm for 5 minutes to obtain an emulsifier. The obtained emulsifier was in a liquid form in which carboxymethyl cellulose was suspended in water.

The obtained emulsifier was added to a mixture of water: edible oil (canola oil) = 50:50 (mass ratio), and the ratio of carboxymethyl cellulose to the total of water, edible oil and emulsifier (including water and carboxymethyl cellulose). Was added so as to be 0.5% by mass. When the emulsion was prepared by stirring for 5 minutes using a homomixer (6000 rpm) and allowed to stand at room temperature for 1 week to visually check the emulsified state, no separation between the aqueous medium and the oil-based medium was observed. It maintained emulsification.

(Example 2)
The sodium salt of carboxymethyl cellulose obtained in Example 1 was added to a mixture of water: edible oil (canola oil) = 50:50 (mass ratio) with water, edible oil and an emulsifier (including water and carboxymethyl cellulose). Addition was made so that the ratio of carboxymethyl cellulose to the total was 0.5% by mass. When the emulsion was prepared by stirring for 5 minutes using a juicer mixer (10500 rpm) and allowed to stand at room temperature for 1 week to visually check the emulsified state, no separation between the aqueous medium and the oil-based medium was observed. It maintained emulsification.

(Comparative Example 1)
The same procedure as in Example 2 was carried out except that powdered cellulose KC Flock W-50GK (manufactured by Nippon Paper Industries, Ltd., median diameter 45 μm) was used instead of the sodium salt of carboxymethyl cellulose of Example 2. The mixture was stirred with a juicer mixer, but the aqueous medium and the oil-based medium remained phase-separated, and a stable emulsion could not be obtained.

The results of Examples 1 and 2 and Comparative Example 1 are shown in Table 1.

Claims (12)

An emulsifier containing carboxymethyl cellulose having a carboxymethyl substitution degree of 0.20 or more, a cellulose type I crystallinity of 50% or more, and a median diameter of 10.0 to 150.0 μm. The emulsifier according to claim 1, wherein the degree of carboxymethyl substitution in carboxymethyl cellulose is 0.50 or less. Claim 1 or 2 in which carboxymethyl cellulose is produced by carrying out a mercerization reaction under a solvent mainly containing water and then carrying out a carboxymethylation reaction under a mixed solvent of water and an organic solvent. The emulsifier described in. The emulsifier according to claim 3, wherein the solvent mainly containing water is a solvent containing more than 50% by mass of water. The emulsifier according to claim 3 or 4, wherein the ratio of the organic solvent in the mixed solvent is 50 to 99% by mass with respect to the total of water and the organic solvent. The emulsifier according to any one of claims 1 to 5, further comprising an aqueous medium. A food or drink containing the emulsifier according to any one of claims 1 to 6. A cosmetic product containing the emulsifier according to any one of claims 1 to 6. A coating material containing the emulsifier according to any one of claims 1 to 6. The step of adding the emulsifier according to any one of claims 1 to 6 to a mixture of an aqueous medium and an oil-based medium to prepare the mixture of the emulsifier, the aqueous medium, and the oil-based medium, and the emulsifier. A step of preparing an emulsion in which an aqueous medium and an oil-based medium are emulsified by stirring a mixture of an aqueous medium and an oil-based medium.
A method for producing an emulsion, including. The step of preparing a mixture of the emulsifier, the aqueous medium, and the oil-based medium includes adding the emulsifier so that the solid content of carboxymethyl cellulose in the emulsion is 0.05 to 1.00% by mass. The method for producing an emulsion according to claim 10. The method for producing an emulsion according to claim 11 or 12, wherein in the step of preparing the emulsion, stirring is performed at a rotation speed of 1000 to 15000 rpm for 1 minute or more.